Adjustable bracket



v 2Sheets-Sheet 1. W. S; HOW.

y ADJUSTABLE BRACKET. No. 316,459. Patented Apr.' Z8, 1885.

Y 2 Sheets-Sheet 2 W.- S. HOW.

ADJUSTABLE BRAGKBT. No. 316,459. Patented Apr. 28, 1885n G l' XV? :il I l l1 gm'ai" lt y 1 t i fllllllll 1M l la WUT'NESSES l, Iwmwfol;

llamen Sl'rarrs l errar riviera WOODBURY STORER HOW', OF CINCINNATI, OHIO, ASSIGNOR TO THE S. S. WHITE DENTAL MANUFACTURING COMPANY, OF PHILADELPHIA, PA.

ADJUSTABLE BRACKET.

l SPECIFICATION forming part of Letters Patent No. SIGA-59, dated April 28, 1835.

' .applicatif n tiled December 81, 1878.

T all whom t may concern,.-

Be it known that I, WOODBURY S. How, of Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Adjustable Brackets and in the Method of Hanging or Mounting them, of which the followingis aspecification.

My invention relates more particularly to adj ustable brackets ofthe class in which a table ro or tray is supported by a frame in a horizontal position, while capable of vertical adjustment in the arc of a circle, (substantially,) the tablecarrying frame being jointed to the outer ends of parallel arms, while the inner ends of said arms are jointed to a suitable support.

The objects of my invention more especially are, first, to improve parallelarmed brackets by rendering them capable of more easy operation, and with but little exertion on the part 2o oi' the operator; second, to provide an in1- proved construction of clamping or locking device at the outer ends of the parallel arms, whereby the table or tray may be conveniently and positively locked at any point in its range :5 of vertical adjustment; third, to provide for the longitudinal extension of the table-supporting arm in asuperior manner,so as to avoid the tendency ofthe extensible arm of the bracket to bind or stick in its socket or support.

My object, further, is to improve the construction of brackets so as to render them more useful, and to facilitate the operations of persons-dentists, for example-who may use them.

The subject-matter claimed by me herein is rst fully described, and then particularly pointed out at the close of the specification.

The accompanying drawings show my improvements as organized in the best way now 4o known to me. It will be understood, ofcourse,

however, that changes may be made in the organizations shown without departing from my invention, and that some of my improvements may be used without the others, and in brackets differing from those shown in saiddrawings, and particularly described herein.

In said drawings, Figure l is a side elevation of one form of my improved bracket, and Fig. 2 is a similar view from the opposite side 5o thereof. Fig. 3 is a vertical section through the bracket on the line 3 3 of Fig. 2, showing particularly the construction ot' the clamp which positively locks the outer ends of the parallel arms, and also the construction of the spring clamp-socket in which the sliding extension-arm of the bracket is carried. Fig. 4 is a section through the bracket on the line 4 4 of Fig. 2, showing particularly the spring clamp-socket of the sliding extension-arm above referred to. Fig. 5 is a view in eleva- 6o tion of a modified form of bracket, showing a different organization of counterbalancing or equipoising springs from that shown in Fig. y l, also a modified forni of' clamp for the parallel arms, and also a ditl'erent form of seat 65 for the sliding extension-arm which carries the table or tray; and Fig. 6 is a section therethrough on the line 6 6 ot' Fig. 5. Fig. 7 is a View in elevation of still another modification of my improvements, the equipoising or coun- 7o terbalancing oi' the load at the outer ends of the parallel arms being effected by an adjustable weight instead of by a disposition of a spring or springs, as shown in Figs. 1, 2, and 5; and Fig. Sis a view in elevation, partly in 75 section, of a simple` form of bracket unprovided with the parallel arms,l but having the same description of seat for the sliding extension-arm as that shown in Fig. 5.

In the organization of the brackets shown 8o in the drawings a crane-plate, A, is pivoted to the wall or some other support, so as to be capable of turning horizontally, the connection being formed in the examples illustrated in lall instances, save in Fig. 7, by vertical pivots a a of the crane-plate fitting suitable seats or sockets in projecting lugs or supports b b', attached to the wall B, for instance. I prefer the lower lug, b', to be provided with a tapering seat or socket for the lower taperL 9o ing journal or pivot, a', ofthe crane-plate A, whereby, owing to the large frictional surface of the lower pivot, the crane-plate will have a tendency to remain stationary when adjusted, and will require more power to move it on its pivots than if both pivots or journals of the crane-plate were plain or straight pivots. This is important in that it conduces to a bracket the movements of which are steady and solid. roo

Parallel arms C C are pin-jointed at their inner ends to the crane-plate A, while their outer ends are similarly jointed to one side of the frame D, which I will call a horizontal frame, inasmuch as it remains horizontal or in a constant plane notwithstanding vertical adjustment in a curved path.- This horizontal frame in the present instance consists of a flat plate carrying in Figs. l, 2, 3, 4, 5, and 6 a box or seat for the reception of a longitudinally-extensible arm, E, carrying at its outer end the table or tray of the bracket. In Fig. 7the horizontal frame D is provided with a fixed arm, upon which the table or tray is mounted. The same pivots which unite the outer ends of the parallel arms to the horizontal frame also pass through a link-clamping plate, F, fitted on the opposite side of said arms in such manner that said plates D and F are loosely united by said pivot-pins with the ends of the parallel arms between them, and said arms are loosely jointed to said plates.

In order to positively clamp the horizontal frame-plate D and clamp-plate F together and to the outer endsof the parallel arms C C, so as to lock said arms and the horizontal frame at any point desired in theirrange of vertical movement, whereby to sustain the arms in a said plates D F, and preferably between the p outer ends of the parallel arms in the organizations shown in Figs. 1, 2, and 3, whereby, by tightening a clamp-nut, c', upon the threaded part of said screw, the plates D F are tightened upon the ends of the arms C C or are loosened by the reverse movement of said nut, as the case may be, whereby a ready means is afforded for clamping or releasing both the parallel arms by a single clamp,' which in its effective action and convenience is much superiorto, for instance, clamping the arms each by a separate clamp .or device, which I desire here to acknowledge to be old and not of my invention, or of clamping both arms to the horizontal frame by a curved slotted plate and thumb-nut, 'which I also here acknowledge to be old.

In the construction of bracket shown in Figs.

5, 6, and 7 the locking-clamp is formed by making one of the pivots of the outer ends of the parallel arms in the form of a set-screw having a handle at one end, while the screwthreaded shank passes through the clampplateF and parallel arm and into a female thread in the horizontal frame-plate D. By tightening or loosening this screw the end of `the parallel arm will be clamped between the 'zonta-l frame-plate D, for instance, with which- Aits seat.

the point of the pawl P, pivoted on one of the arms C, engages, as clearly shown in Fig. 2. This pawl is weighted at its lower end to automatically engage its upper locking end with the ratchet-teeth d, and the weighted end is shaped so as to constitute the lower end of the pawl a convenient handle by which to operate it to disengage its upper vend from the ratchet-teeth when the table is to be adjusted. As soon as released the pawl automatically engages the ratchet.

The horizontal frame-plate D in the organization shown in Figs. l, 2, 3, and 4 carries a spring leaf or portion, d, bent so as to form a tubular seat or recess for the vreception of the extensionarm E, whichl may be moved ,freely endwise in said seat when expanded, in

order to extend or contract the length of the bracket. This extension arm is preferably hollow for lightness, and is also preferably provided with a fiat side next the frame-plate D, instead of being circular in cross-section, whereby the extension-arm, while capable of being moved freely endwise, cannot turn in When unrestrained,the tendency of the tubular clamp is to separate or expand, so as to enlarge the seat of the extension-arm E, and thus lpermit said extension-arm to be ymoved or adjusted endwise with great freedom and without the binding or sticking action to which the similar arms of all brackets heretofore constructed of which I am aware are liable.

In order to contract the clamp so as tolockl .the extension-arm in any position to which it lmay be adjusted, I have provided the hori-` zontal frameplate D with a set screw, the threaded end of which is extended through the extension or flap d of the spring-clamp into the frame-plate D, whereby by tightening the said screw the tubular seat of the clamp yis contracted and caused to bind throughout capable of being turned freely horizontally on saiduarm; and instead of the plain ordinary pivotal'connection usually employed for this purpose, I prefer that the pivot be tapered, so as to increase the frictional surface and cause the table to remain fixed unless positively turned. In some instances the extensible arm E, instead of being adjustable in'y a tubular spring-clamp suoli as I have shown and described, may be adjustable in a box carried by the horizontal frame, which islined or IIO packed .with a dry nonmetallic anti.- friction substance-suchas wood or leather-'- which permits free endwise movement of said of bracket shown in said ligure the craneextensible arm without binding or sticking in l its seat. A box or casing lined or provided with a nonmetallic l'iushingis shown in Figs. 5, 6, and 8.

In Fig. 8 the extensible arm E is tted to slide in a seat in an arm connected directly with the crane-plate or tothe wall, and without the intervention of the parallel arms which afford vertical adjustment.

In some instances the table or tray will be mounted directly upon or be carried by the horizontal frame D, and not by said frame through the medium of an extensible arm. In other words, in some instances the extensible arm tted on the bracket may be dispensed with-as in Fig. 7, for example. In the form plate A is pivoted to the outer end Aof the swinging` or folding arm H, which permits of extending the table or tray more or less from the wall or support of the bracket.

In order to render the bracket vertically adjustable with ease and with but little exertion on the part of the operator, I have, afterlong study and repeated experiment, devised a method of and means for counterbalancing the weight of the pivoted bracket-arms and table so that the parallel arms and table at their outer ends are in equipoise, and will remain in the position vertically to which they are moved without the aid of locking or clamping devices. It will thus be seen that in moving the table up or down but slight ei'iort is required,there being practically no weight either to lift when moving the table upward or to sustain when adjusting the table to a lower position. vVhen adj usted, a clamping or looking device may, if desired, be operated to positively fix the table in its adjusted position. This arrangement for preserving the equipoise of the arms and table in their limited vertical range of movement may consist either of a spring or springs or of a weight, the organizations of which I will now particularly describe.

In Figs. l and 2 I have shown two springs, I I', connected to the crane-plate and one to each of the parallel arms C C. The lower spring, I, is a coil-spring connected at its outer end to the lowermost of the parallel arms, at or about the center of said arm, by means of a hooked pin, z', and at its inner end to the crane-plate by a similar hooked pin, i', at a point a short distance above the pivotal point of the arm upon the crane-plate, as clearly shown in Figs. l and 2. Vith the spring lying in nearly the same line as the arm with which it is connected, as shown, said spring has the effect of keeping the arm and table in equipoise, its action being such that its tension or power increases or decreases in proportion to the increase or decrease of leverage of the parallel arm Within its range of movement upon its pivotal connection with the crane-plate A, which range of movement is limited by contact ofthe parallel arms or of the adjustment of the bracket is suitable stops thereof.

The line of action of the coil-spring lnay be varied within certain limits, while still substantially retaining the equipoise of the parts; but a wide departure from the organization shown radically changes the action of the spring, and while up to a certain pointit may act to sustain the weight of the arms and table, still above that point it will not sustain the load, and if the table be carried below the point of sustentation by force and then released the spring will react and draw or throw the table quickly back. An example of such an organization of a spring witha parallel-armed bracket is shown in the Dental Advertiser (volume 8) for 1877, page lll; but such an ar rangement is radically different from the 0rganization devised by me. In one case the spring is a reacting or returningspring tosustain a part of the weight of the arms and its table-load, while in my case an equipoise of the arms and load throughout their range ot' movement is effected. It is suggested in the form of device shown in the Advertiser, above alluded to, that, owing to the size and number of the bearings, (joints or pivots) a moderate degree of tightness, in connection with the spring, will render the bracket self-sustaining without recourse to clamping devices or ratchets. In my invention the parallel arms are loosely pivoted, and the spring or weight alone affects the equi poising of the bracket, whereby very easy, which is not the case with the bracket shown in the Advertiser, where the i'riction of tight ened joints has to be overcome in adjusting the bracket. It was to avoid this very thing that my improvements in this direction were devised.

The equipoise coil-spring may be duplicated--that is, an additional spring of the same character may be similarly connected to the uppermost of the parallel arms, as shown in Fig. 5. These springs are adjustable in this instance at their inner ends by means of their connecting-pins z, which are fitted for insertion in any one o'f a series of holes, fig, in the crane-plate, the line of holes preferably being in the are of a circle, as clearly shown in Fig. 5. It will be understood, however, that various other ways of adjusting the springs may be employed without departing from my invention, some of which will be obvious to skilled mechanics. This adjustability of the spring is to compensate variations in the load which the table or tray is designed to carry.

Instead of duplicate springs, only one spring may be used, and that may be an arm or lever spring, as clearly shown in Figs. l and 2. This spring is fitted to and coiled at its inner end around a stud or post on the crane-plate, while its lever-arm is passed under a hook or projection on one of the parallel arms at or about its conter. The organization is such that any downward movement ofthe parallel arms from the extreme limit of their upward movement causes the hook or projection to move endwise on the spring-arm, and also to bend said arm IOU i a weight may be employed, as clearly shown in Fig. 7. ln this modification the upper parallel arm is carried back beyond its rear pivotal connection with the crane-plate A, and the weightis mounted on the inner end of said extended arm. Said weight is adjustable by means of the row of holes, for example, for the same purpose as the spiral springs before described, and the action in maintaining the equipoise of the bracket-arms and table is substantiall y the same.

I do not claim in this application the specic arrangement of the weight for maintaining the equipoise of the bracket, nor mounting the parallel arms by their turning-crane connection upon a folding arm, nor the lined or bushed box or casing in which the extensi ble arm E is fitted, northe automatic locking device herein described. These parts or features of my invention will be embodied in a division of this application to be led.

I claim as my invention- 1. The combination, substantially as hereinbefore set forth, of the cranefplate, the loosely-pivoted vertically-adj ustable parallel arms, and an equipoising device, substantially as described, whereby said arms are maintained in equipoise at different points in the range of 4o 3. The combination, substantially as hereinbeforc set forth, of the pivoted'parallel arms, the horizontal frame jointed to one side' ofthe outer ends of said arms, the clamp-plate jointed to the other side ofsaid outer ends of said arms, and by the same pivots that joint the parallel armsA and horizontal frame together, and al clam p-screw passing through said horizontal frame and said clamp-plate.

4. The combination, substantially as hereinbefore set forth, of the horizontal frame at the outer ends of the pivoted parallel arms, an expansible and contractible spring socket or box carried by said frame, and an extensionrod fitted to move endwise in'said socket when expanded, and be locked at the point desired by contracting said socket. i

In testimony that I claim the foregoing as my own I affix my signature in. presence of two witnesses.

WOODBURY STORER HOW.

- IVitnesses:

THos. AMBRosE, HERBERT D. BLAKEMORE. 

